Needle positioner



Jan. 10, 1961 s. M. COHEN NEEDLE POSITIONEIR 3 Sheets-Sheet 1 Filed Oct.5, 1959 INVENTOR 5/704 M Cams/v ATTORNEY Jan. 10, 1961 s. M. COHEN2,967,499

NEEDLE POSITIONEIR Tull.

Filed 001;. 5, 1959 3 Sheets-Sheet 2 INVENTOR 51 M Joya/v ATTORNEY ,Unted s t NEEDLE POSITIONER Saul M. Cohen, Paramus, N.J., assignor toClinton Ingristiies, Inc., New York, N.Y., a corporation of New FiledOct. 5, 1959, Ser. No. 844,545

14 Claims. (Cl. 112-219) The present invention relates generally toimprovements in sewing machines. In particular, it relates to animproved mechanism for automatically bringing or halting the needlesupporting bar of a sewing machine in any desired preselected positions.

In commercial and industrial sewing operations, stopping of the sewingmachine with the needle in its raised or depressed position is a veryfrequent requirement. Since it is necessary, in operation ofconventional sewing machines, to stop or to slow down the sewing machineand then to manipulate it in order to bring the needle to the desiredposition, the needle-positioning operation consumes a substantial partof the total sewing operation thereby to increase materially the overallcost of the item being sewn. Automatic needle-positioning mechanismshave been heretofore proposed and employed, but these have possessednumerous drawbacks and disadvantages. They are awkward, costly andcomplex mechanisms subject to frequent malfunctioning. In addition, theyare diflicult to attach to the conventional sewing machine, requiringconsiderable modification of the sewing machine, and otherwise leavemuch to be desired.

It is thus a principal object of the present invention to provide animproved sewing machine.

Another object of the present invention is to provide an improvedmechanism for automatically bringing the needle of a sewing machine topreselected positions.

Still another object of the present invention is to provide an automaticneedle-positioning mechanism which may be simply and readily attached toa conventional sewing machine.

A further object of the present invention is to provide an improvedautomatic needle-positioning mechanism of the above nature which ischaracterized by its structural ruggedness, simplicity of operation,reliability in performance, and of low cost.

Still a further object of the present invention is to provide animproved shaft-coupling device of novel properties.

The above and other objects of the present invention will becomeapparent from a reading of the following description taken inconjunction with the accompanying drawings, wherein:

Figure l is a perspective view of a sewing machine employing theimproved automatic needle-positioning mechanism according to the presentinvention;

Figure 2 is a top plan view of the improved automatic needle-positioningmechanism, partially broken away and partially in section;

Figure 3 is a sectional view taken along line 3-3 of Figure 2;

- Figure 4 is a sectional view taken along line 4-4 of Figure 3;

, Figure 5 is a sectional view taken along line 5-5 of ;.Figure. 3;

, Figure 6' is a sectional view taken along line 6-6 of Figure 3;

2,967,499 Patented Jan. 1Q,

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Figure 7 is a sectional view taken along line 77 of Figure 3; and

Figure 8 is a schematic view of the electrical network employed with theautomatic needle-positioning mechan.sm.

A feature of the present invention resides in the provision of a novelcoupling mechanism between the sewing machine per se and the main drivemotor, which coupl.ng comprises a driven shaft connected to said sewingmachine, a drive shaft connected to said motor, first and secondoppositely sensed unidirectional rotary coupling devices connecting saidshafts, and means selectively disabling one of said coupling devices. Inorder to position the sewing machine needle bar automatically, there isprovided an auxiliary positioning motor which is connected to thecoupling mechanism driven shaft by way of an over-running clutch whicheffects a forward drive to couple the disabling means, being solenoidactuated and associated with the backward drive coupling between theshafts. A selectively operable first switch means connects the auxiliarymotor and the disabling solenoid to a source of current through anormally closed second switch actuated by an element carried by thedriven shaft to open the latter switch when the needle bar is in apreselected positon. Means are also provided for momentarily reversingthe auxiliary motor to assure the prompt stopping thereof.

In effecting the automatic positioning operation, the machine operatormerely stops and brakes the main drive motor and closes the first switchto energize the auxiliary motor and disable the shafts rearward drivecoupling to permit the advance of the driven shaft while the drive shaftis stationary. The driven shaft advances the needle bar to its desiredposition, whereupon the second switch is automatically opened to stopthe needle bar in said position. Switch means are also providedpermitting moving of the needle bar automatically to a plurality ofselected positions. v

In accordance with a preferred embodiment of the present invention, thedriven shaft is a hollow shaft te'esroped by the drive shaft. Two setsof end-to-end ax'ally arranged cylindrical clutch surfaces are carriedby the shafts, one set of surfaces being concave and the other convex.Similarly sensed helical coupling springs tightly register with theclutch surfaces whereby one set is coupled in a forward drive andbackward'slip d'rection and the other set is coupled in a backward driveand forward slip direction so that the shafts are normally rigidlycoupled. Means are provided to disable the backward drive couplingspring by partially unwinding the same. The auxiliary motor is coupledto the driven shaft by a forward drive coupling of a similarconstruction. Disabling the shaft backward drive coupling permits theadvance of the driven shaft by the auxiliary motor while the drive shaftis braked. Y

Referring now to the drawings which illustrate a preferred embodiment ofthe present invention, reference numeral 10 generally designates asewing machine employing the improved automatic needle-positioningmechanism which includes a support table 11, a sewing machine head 12and needle-positioning mechanism 13. Table 11 comprises a top orplatform 14 supported on legs 16 and having mounted on its top facesewing machine head 12 and positioning mechanism 13, and on its bottomface a main drive motor 17. Drive motor 17 is of conventionalconstruction, provided with a shaftmounted drive pulley 18 andcontrolled through an arm 19 connected to a foot treadle 20, and beingof the type nected by way of any well known motion-translating mechanismto sewing machine drive pulley 22.

The automatic needle-positioning mechanism is paritially housed in acasing 23 and comprises a tubular driven shaft 24 and a drive shaft 26telescoping the shaft 24 and extending beyond the opposite ends thereof.

Shafts 24 and 26 are rotatable relative to each other and the assemblythereof is rotatably supported by a pair of longitudinally spaced ballbearings 27 which are carried by upright brackets 28 and which engageshafts 24 and 26 respectively.

A pulley 29 is mounted on an end of drive shaft 26, designating theinner end thereof, and is afiixed thereto by means of a set screw 30engaging a tapped radial .bore in the pulley hub and a shaft recess. AV-belt 31 connects pulley 29 to drive motor pulley 18. A second pulley32 is affixed to the end of driven shaft 24 adjacent pulley 29 and isaffixed thereto by a hub carried Set screw 33. Pulley 32 is, in turn,connected to the sewing machine drive pulley 22 by slip-proof belt 34. Apair of separator washers are carried by the shaft 26 between the pulley29 and the confronting end of shaft 24, one of said washers 25 engaginga corresponding peripheral groove in shaft 26 to limit the relativelongitudinal movement of said shaft 24. The inner race of thecorresponding ball bearing 27 is embraced by a hub end face of pulley 32and a washer 36 which is positively positioned by a collar 37 affixed tothe shaft 24 by a set screw 38, the collar 37 having a cammed peripheralsurface to define a switch actuating member.

-In order to effect a drive coupling between the shafts 24 and 26, afirst clutch member 39 is provided, defined by a collar 40 located atthe opposite, outer end of drive shaft 26 and aflixed thereto bykey-engaging corresponding key ways. Collar 40 is provided with anoutwardly directed sleeve flange 41 registering with the bore of thecorresponding ball race 27 and having a peripheral shoulder at its baseabutting the ball bearing inner race. Projecting inwardly from thecollar 40 and formed integral therewith is a clutch cylinder 42 havinginner and outer clutch surfaces 43 and 44 respectively, coaxial withshafts 24 and 26, inner clutch surface 43 being spaced from the surfaceof shaft 26. Annular shoulders 46 project radially from the bases ofclutch surfaces 42 and 43.

A second clutch member 47 is provided, and is defined by a collar member48 affixed to the outer end of tubular shaft 24 by means of set screw 49engaging a tapped radial bore in collar 48 and an aligned bore in shaft24. Clutch 47 includes a cylinder 50 extending outwardly beyond theouter end of the shaft 24 and terminating in a flat end face closelyabutting the corresponding inner end face of first clutch cylinder 42.Clutch cylinder 50 is provided with inner and outer cylindrical clutchsurfaces 51 and 52 respectively, which are in coplanar alignment withcorresponding first clutch surfaces 43 and 44. The base of clutchsurface 52 terminates in an annular shoulder 53, the outer edge of whichjoins a cylindrical shoulder 54 connected by way of an annular step 55to an inner peripheral lip 56. Clutch 47 also includes a thirdcylindrical portion 56a having an outer axial cylinder clutch surface 57and an inner end surface abutting the outer surface of shaft 24.

Rotatably engaging tubular shaft 24 is a sleeve 58,

entrapped between and abutting confronting end faces of collar 37 andclutch cylinder 56a. A sprocket wheel 59 is mounted on sleeve 58 andincludes a cylindrical hub 60 registering with the outer end of sleeve58 and affixed thereto by means of a suitably engaged set screw. Theouter surface of the hub 60 defines a cylindrical clutch surface 61which is in coplanar end-to-end alignment with clutch surface 57.Sprocket wheel 59 is connected by way of a sprocket chain 63 to asprocket wheel 64 mounted on the driven shaft of a suitably mounted,reversible, auxiliary positioning motor 65 of the gear reduction type.Shafts 24 and 26, and the various members carried thereby, are locked inassembled position by a washer and nut 66 engaging a threaded shank 67extending axially from the outer end of shaft 26.

A first helical coupling spring 68 is wound about and tightly engagesthe outer clutch surfaces 44 and 52 extending from shoulder 46 toshoulder 53, and terminating at its inner end in a radially outwardlydirected leg 69. A second helical coupling spring 70 is tightly embracedby the inner clutch surfaces 43 and 51 and extends from shoulder 46 tothe outer end face of the tubular shaft 24. In addition, a third helicalcoupling spring 71 is wound about and tightly embraces the cylindricalclutch surfaces 57 and 61 and extends from the end face of sprocketwheel hub 60 to the confronting face of collar 48.

In the embodiment illustrated, helical springs 68, 70 and 71 are eachright handed, and the forward drive direction is clockwise as viewedfrom the right hand end of Figure 3. Thus, helical spring 70 etfe;tsonly a forward coupling of drive shaft 26 to driven shaft 24 and definesa forwardly sensed over-running clut:h with clutch surfaces 43 and 51,since upon forward rotation of shaft 26 relative to shaft 24, spring 70is partially unwound to expand and tightly engage and rotatably coupleclutch surfaces 43 and 51, and upon backward rotation of shaft 26relative to shaft 24 the spring 70 is partially wound and contracted soas to loosen the engagement between the spring 70 and the clutchsurfaces, and to cause mutual slippage therebetween.

On the other hand, helical spring 68 effects only a backward coupling ofdrive shaft 26 to driven shaft 24 and defines, with clutch surfaces 44and 52, a backwardly sensed over-running clutch, since upon backwardrotation of shaft 26 relative to shaft 24 spring 68 is wound and closelycontracts about clutch surfaces 44 and 52 to effect a vtightinterengagement therebetween, and upon forward rotation of shaft 26relative to shaft 24 spring 68 is partially unwound and expanded so asto loosely engage clutch surfaces 44 and 52 and permit slippagetherebetween. Moreover, spring 71 effects only a forward coupling fromsprocket wheel 59 to driven shaft 24 and defines, with clutch surfaces57 and 61, a forwardly sensed over-running clutch, since forwardrotation of sprocket wheel 59 relative to shaft 24 results in a windingand contraction of spring 71 and a tight interengagement between spring71 and clutch surfaces 57 and 61, and a backward rotation of sprocketwheel 59 relative to shaft 24 results in an expansion and loosening ofspring 71 and slippage between spring 71 and surfaces 61 and 57. As aconsequence of the above-described over-running clutch arrangement,shafts 24 and 26 are normally rigidly coupled in both directions so thatshaft 24 may be driven by shaft 26, and upon disabling coupling spring68 shaft 24 may be rotated only in a forward direction by sprocket wheel59 through spring 71.

The mechanism for disabling backward coupling spring 68 includes a firstcollar 72 rotatably carried by clutch collar 48 and engaging shoulder 54and opposite cylindrical surface of collar 48. Spring leg 69 registerswith an opening 73 formed in collar 72. A second collar 74 encirclescollar 72 and is longitudinally slidable relative thereto, beingprovided with a peripheral flange 76 at its inner end which is movableinto abutment with collar step 56. A screw 77 engages the wall of collar72 and is provided with a head 78 which slidably registers with ahelical slot 79 formed in collar 74, see Fig. 2. Also formed in collar74 are a pair of oppositely disposed longitudinally extending slots 80(see Fig. 4) which are slidably engaged by corresponding pins 81extending radially from clutch collar 48 to limit collar 74 to relativelongitudinal movement. Thus, movement of collar 74 to the right as seenin Fig. 3 of the drawings causes a relative backward rotation of collar72 by way of slot 79 and screw 77 partially to unwind and to disablecoupling spring 68 and open the correspondingly defined backwardlysensed clutch. It should be noted that collar 74 '5 is normally in itsretracted position, with collar 72 in advanced position and spring 68 inits normally wound position.

In order to eflfect selective movement of collar 74 and the disabling ofspring 68, there is provided a yoke or fork member 82 straddling collar48 and having a face abutting the inner face of collar flange 76.Projecting rearwardly from yoke 82 is an arm 83 which terminates in aknuckle 84 rotatably engaged by a suitably supported vertical pin 86. Aleg 87 projects from knuckle 84 in a longitudinally extending directionand terminates in a depending pin which engages a slot 88 formed in areciprocable armature 89 which is spring urged to an advanced positionas illustrated in Fig. 2, and is drawn to a retracted position upon theactuation of an associated solenoid 90 to disable coupling spring 68 bysliding collar 74 outwardly by reason of the advancement of yoke 82.

Straddling sleeve 58 between sprocket wheel 59 and cam 37 is asemicylindrical yoke 91 having an inwardly directed lip 92 engaging acorresponding peripheral groove in sleeve 58. A circular helical tensionspring 94 rests in a groove formed in yoke 91 and engages the oppositesurface of sleeve 58 to effect a friction slipping engagement betweenyoke 91 and sleeve 58. Rotary motion of yoke 91 is limited to a slightrocking by a pair of oppositely disposed abutment members 96 and 97 (seeFig. 6)

having upwardly directed faces confronting the downwardly directed endfaces of yoke 91. Located adjacent yoke 91 is a suitably mounted,normally open switch 98, having an upwardly sprung resilient actuatingarm 99, the free end of which arm engages the leading end face of theyoke 91. Switch 98 is closed by the forward rotation of sleeve 58 andsprocket wheel 59, and returned to its normaly open position uponbackward rotation thereof.

A pair of circumferentially spaced switches 100 and 101 are suitablymounted (see Fig. 7) in the vicinity of switch actuating cam 37, eachswitch having respectively 'associated therewith a resilient actuatingarm 102 and sewing machine needle bar 21 is in raised position andswitch 101 is opened when the needle bar is in depressed position.

Referring now to Figure 8 of the drawings, which illustrates theelectrical network of the automatic needle positioner of the presentinvention, the reversible motor 65 includes a rotor 106 and a fieldwinding 107. There is provided a relay 108 including an actuatingsolenoid 109, a pair of arms 110 and 111 normally engaging contacts 112and 113 respectively, and upon energization of solenoid 109 engagingcontacts 114 and 115 respectively and disengaging contacts 112 and 113.The terminals of motor field 107 are connected to'relay arms 110 and111,

and the motor will be driven in reverse when relay 108 is deactivatedand arms 110 and 111 engage contacts 112 and 113 and forward when relay108 is actuated and arms 110 and 111 engage contacts 114 and 115. Relaycontacts 112 and 115 are connected together through motor armature 106to a first terminal 117 of a suitable source of current including anopposite terminal 118. Relay contact 113 is connected through switch 98and a main switch 120 to current source terminal 118, and relay contact114 is connected to the current terminal 118 through the switch 120.Solenoids 90 and 109 are parallel-connected between current terminal118, by way of switch 120, and a terminal of each of the switches 100and 101, which are interconnected. The opposite terminal of switch 100is connected through a switch 121 to a normally closed contact 122 ofadouble throw switch 123,- the arm 125 of which is connected to currentterminal-117, and the opposite terminal of switch 101 is connected tothe normally open terminal 126 of switch 123. Switch 121 is selectivelyoperable, and is preferably coupled to foo-t treadle 20 so as to closeswitch 121 when treadle 20 is raised and main motor 17 braked, and toopen switch 121 upon depression of treadle 20. Switch 123, on the otherhand, may be so located as to be operable selectively by a knee lever127 carried on the underface of table top 14.

The operation of the automatic needle positioner is apparent from theabove description. When the machine is actuated for normal sewingoperation, foot treadle 20 is depressed and knee lever 127 released; themain motor 17 being energized thereby and driving the machine by way ofpulley 29, shaft 26, clutch members 39 and 47 and coupling spring 70,shaft 24 and pulley 32. Solenoids 90 and 109 are deenergized by reasonof switch 121 and contact 126 being open, and the auxiliary motor 65 isdeenergized by the automatic opening of switch 98 in the mannerpreviously described, and contacts 114 and 115 being open. When it isdesired to stop the sewing machine in the needle-raised position, foottreadle 20 is released, deenergizing and braking main motor 17 andstopping the sewing machine by way of shafts 24 and 26, which arereverse-coupled by spring 68 as earlier set forth to preventover-running of the sewing machine. The release and raising of treadle20 also completes the power circuit to solenoids 90 and 109 by way ofswitch 100, energizing solenoid 90 and disabling spring 68 therebytopermit the advance of shaft 24 relative to shaft 26 and energizingsolenoid 109 to bring relay arms motor field and armature across to thepower source in a forward drive sense. The energized advancing auxiliarymotor closes switch 98 and drives the sewing machine by way of sprocketwheel 59, forwardly sensed coupling spring 71, shaft 24 and pulley 32until the needle bar reaches its raised'position, at which point cam 37opens switch 100 to deenergize the solenoid and return spring 68 tocoupling position and lock needle bar in raised position, and todeenergize relay solenoid 109 returning relay arms 110 and 111 to thefield-reverse "position, the auxiliary motor 65 being connected to thecurrent source by closed switch 98. Motor 65 is thus rapidly stopped andrun in a reverse direction a short distance sufficient to permit theopening of switch 98 by yoke 91 as aforesaid. The motor can freely runin a reverse direction by reason of the slippage of coupling spring 71.Furthermore, the forward rotation of shaft 24 is not transmitted tomotor 65 by reason of said coupling spring slippage. When it is desiredto bring the machine to a needle depressed position, switch 123 isactuated by knee lever 127 and treadle 20 released. This substitutesswitch 101 in the circuit for switch thereby to stop the needle bar inits depressed position upon the opening of switch 101 by cam 37. Thesequence of operation is otherwise similar to that previously describedin connection with the stopping of the machine in the needle bar-raisedposition.

While there has been described and illustrated a preferred embodiment ofthe present invention, it is apparent that numerous alterations,omissions and additions. may be made without departing from thespiritthereof.

What is claimed is:

1. An improved sewing machine of the character described, comprising areciprocable needle bar, a main drive motor, a driven shaft connected tosaid needle bar, a drive shaft connected to said main motor, first andsecond oppositely sensed overrunning clutches connecting said shafts,means for disabling one of said clutches, an auxiliary positioningmotor, and means including a third overrunning clutch connecting saidauxiliarymotor to said driven shaft.

2. An improved sewing machine of the character described, comprising areciprocable needle bar, a main drive motor, a driven Shaft connected tosaid needle bar, a drive shaft connected to said main motor, a firstoverrunning clutch connecting said drive shaft to said driven shaft in aforward coupling sense, a second overrunning clutch connecting saiddrive shaft to said driven shaft in a backward coupling sense, means forselectively disabling said second clutch, an auxiliary positioning motorand means including an overrunning clutch connecting said auxiliarymotor to said driven shaft in a forward coupling sense.

3. An improved sewing machine of the character described, comprising areciprocable needle bar, a main drive motor, a driven shaft connected tosaid needle bar, a drive shaft connected to said main motor, a firstoverrunning clutch connecting said drive shaft to said driven shaft in aforward coupling sense, a second overrunning clutch connecting saiddrive shaft to said driven shaft in a backward coupling sense, means forselectively disabling said second clutch, an auxiliary positioningmotor, means including an overrunning clutch connecting said auxiliarymotor to said driven shaft in a forward coupling sense, and meansselectively substantially concurrently actuating said clutch disablingmeans and energizing said auxiliary motor.

4. An improved sewing machine of the character described, comprising areciprocable needle bar, a main drive motor, a driven shaft connected tosaid needle, a drive shaft connected to said main motor, a firstoverrunning clutch connecting said drive shaft to said driven shaft in aforward coupling sense, a second overrunning clutch connecting saiddrive shaft to said driven shaft in a backward coupling sense, means forselectively disabling said second clutch, an auxiliary positioningmotor, means including an overrunning clutch connecting said auxiliarymotor to said driven shaft in a forward coupling sense, meansselectively substantially concurrently actuating said clutch disablingmeans and energizing said auxiliary'motor, and means responsive to theposition of said needle bar for deenergizing said auxiliary motor anddeactivating said clutch disabling means.

5. An improved sewing machine in accordance with claim 4, wherein saidauxiliary motor is a reversible type motor, and including means formomentarily reversing said motor following the energization thereof andsaid needle bar reaching said predetermined position.

6. An improved sewing machine in accordance with claim 4, wherein saidauxiliary motor deenergizing means is responsive to said needle being ina raised position.

7. An improved sewing machine in accordance with claim 4, wherein saidauxiliary motor deenergizing means is selectively responsive to saidneedle bar being in its raised and depressed position.

8. An improved sewing machine in accordance with claim 4, includingautomatically operable means braking said main motor upon deenergizationthereof.

9. An improved sewing machine in accordance with claim 4, wherein saidauxiliary motor deenergizing means comprises series-connected,selectively operable first switch and normally closed second switchmeans connecting said auxiliary motor to a source of current, and switchactivating means mounted on said driven shaft and urging said secondswitch to an open position upon said needle bar reaching a predeterminedposition.

10. An improved sewing machine comprising a reciprocable needle bar, amain drive motor, a tubular first shaft, a second shaft telescoping saidfirst shaft, means connecting one of said shafts to said needle bar,means connecting the other of said shafts to said main drive motor, saidfirst shaft having a first pair of axially cylindrical surfaces and saidsecond shaft having a second pair of axially cylindrical surfaces, eachof said second pair of surfaces being in substantially end-to-endcoplanar alignment with a corresponding one of said first surfacesthereby to define first and second sets of clutch surfaces, a first andsecond helical coupling spring registering with each of said sets ofclutch surfaces and affording forwardly and backwardly senseduni-directional connections respectively between said shafts, one ofsaid shafts having a third axial cylindrical surface, a collar rotatableon said latter shaft and having a cylindrical surface in end-to-endcoplanar alignment with said third surface to define a third clutchsurface set, a third helical spring registering with said third clutchurfaces, and an auxiliary drive motor connected to said collar.

11. An improved sewing machine in accordance with claim 10, includingmeans for partially unwinding said first helical spring to effectdecoupling of. said first set of clutch surfaces.

12. An improved sewing machine of the character described, comprising areciprocable needle bar, a main drive motor, a driven shaft connected tosaid needle bar, a drive shaft connected to said main motor, a firstoverrunning clutch connecting said drive shaft to said driven shaft in aforward coupling sense, a second overrunning clutch connecting saiddrive shaft to said driven shaft in a backward coupling sense, solenoidactuated means for disabling said second clutch, an auxiliarypositioning motor, means including a third overrunning clutch connectingsaid auxiliary motor to said driven shaft in a for ward sense, anormally closed first switch connecting said disabling solenoid to asource of current, a switch-actuating element carried on said drivenshaft and opening said first switch when said needle bar is in apredetermined position, and a relay having a set of normally opencontacts connected between said auxiliary motor and a source of currentand having an actuating solenoid connected to a source of currentthrough said first switch.

13. A sewing machine in accordance with claim 12, including a secondselectively-operable normally open switch in series circuit with saidfirst switch.

14. A sewing machine in accordance with claim 13, wherein said motor isof the reversible type and said relay includes a second set of normallyclosed terminals and including a normally open third switch, said motorbeing connected for reverse operation through said normally closed relaycontacts and said third switch to a source of current, and means closingasid third switch upon forward rotation of said auxiliary motor.

References Cited in the file of this patent UNITED STATES PATENTS

